World’s sharpest tip invented in University of Alberta research labs

Ross Vincent
The Gateway (University of Alberta)
EDMONTON (CUP) – A microscope tip built by scientists at the University of Alberta’s National Institute for Nanotechnology has been recognized by Guinness World Records as the sharpest man-made object.
Physics professor Robert Wolkow headed the team that created the prize-winning microscope tip in 2006, and though his goal was to create a more useful tool rather than achieve a record, the award came as a pleasant surprise.
“It’s a measure of accomplishment that most anyone is familiar with, so it resonates with a lot of people. It has an accessible quality […] it’s more like a sporting event than a scientific discovery. It’s just a thing people like to rally around, I guess,” he said.
The tip is composed of tungsten metal that has reacted with nitrogen gas, which carved away the edges, leaving a pyramid shape with a single atom at its apex.
“It’s neat that unlike the fastest hundred-metre dash or something, you can never make a sharper tip than this because you can’t make anything sharper than an atom,” Wolkow said. “I guess people could equal this, but no one will ever be able to displace it, so that’s kind of neat. It should be a permanent record.”
In microscopes, the extremely sharp tip channels a beam of electrons across any sample researchers want to examine. The microscope then detects the electrons as they bounce off the sample’s surface and generates a topographical image of the sample in atomically accurate detail.
Wolkow said this tungsten tip enables a new kind of microscope, one that projects ions rather than electrons. An ion microscope is more accurate and could potentially replace scanning-electron microscopes, which are widely used throughout research and industry.
The unique carving process used to make the new tip was originally discovered by accident, when air leaked into an electron microscope’s vacuum chamber and became reactive, eating away at the metal tip. The reaction leaves an atom-thin layer of nitrogen residue on the tip, making a stable framework for an otherwise unstable stack of atoms.
“People have found ways before to stack up atoms in a pyramid, but interestingly they fall down or flow away to a less sharp shape quite spontaneously,” Wolkow explained. “What we’ve done is […] take away material to reveal a sharp point, [and] paint the remaining surface with a binding layer that makes it robust.”
Wolkow credits the interdisciplinary environment of NINT for drawing his attention to the tip’s potential for use in electron and ion microscopes.
“One of the beauties of NINT is that we bring scientists of different backgrounds together, and we interact and hopefully influence each other and do things that as individuals we couldn’t do, but as interacting scientists, we can do.”
The institute and the U of A jointly hold the patent to the tip. Though it is currently available to researchers around the world, the main goal is to see it commercialized in co-operation with Canadian industries.
The Guinness World Record for sharpest man-made object is one of two such records held by the university, the other being for the largest dodgeball game, achieved in February.